1. Field of the Invention
This invention relates to a method comprising: producing a heavy crude oil from a subterranean formation via a wellbore; diluting the heavy crude oil with a suitable diluent and transporting the heavy crude oil/diluent mixture to a market location; converting the heavy crude oil into a product distillate hydrocarbon stream using a distillation process and a solvent deasphalting process and recovering added values from the residual asphaltic portions of the heavy crude oil in a fluidized bed to produce heat, electricity, steam or synthetic liquid hydrocarbons.
2. Description of Related Art
In many parts of the world heavy crude oils are available for production in remote locations. In such remote locations commonly available utilities such as electricity and steam may not be available at all or may be available only in short supply. In such instances, the only option may be to transport the heavy crude oil in a pipeline to a location from which it may be transported to a refinery. Many of the heavier components contained in the heavy crude oil may not be suitable for distillation into distillate hydrocarbon products and may eventually be converted into asphalt, petroleum coke or the like by currently used methods.
In less industrialized parts of the world there may be little market for such products. As a result the products may be of low value in the accessible marketplace. Alternatively, the heavier components may be blended with lighter oils to produce a heavy fuel oil product. Typically, the market value of such heavy fuel oils is relatively low, especially, when the value of the diluent oil as a distillate product is considered.
Such heavy crude oils in some instances, are so viscous that it may be difficult to recover the heavy crude oils from a subterranean formation initially without admixture of a hydrocarbon diluent with the heavy crude oil in the wellbore to reduce the viscosity of the heavy crude oil. Even if the heavy crude oil is at an elevated temperature in the subterranean formation which is high enough to result in a flowable heavy crude oil at the elevated temperature in the formation the heavy crude oil remains likely to cool and solidify in upper portions of the producing well, especially during any periods where production is stopped for an interval. Similarly the heavy crude oil is likely to cool and solidify in surface pipelines unless required temperatures and flow rates in the surface pipelines can be maintained. As a result typically distillate hydrocarbon diluents (or occasionally other diluents) are mixed with such heavy crude oils either during or after production and before pipelining to prevent solidification of the heavy crude oil in the pipeline.
Such heavy crude oils contain a much higher percentage of non-distillable components than lighter crude oils. Some such heavy crude oils may contain less than 50 weight percent distillable hydrocarbons.
The production and transportation of such heavy crude oils, especially in remote locations, requires that large quantities of hydrocarbon diluent be transported to the remote location via a pipeline, by truck or the like. This hydrocarbon diluent is expensive relative to the heavy crude oil even without considering the added transportation cost. The diluent when mixed with the heavy crude oil may result in a mixture which still contains as much as 45 weight percent residual (non-distillable) materials. Transportation of this mixture requires a larger pipeline and limits the production and transportation of the desired distillable components of the heavy crude oil. Even if transported to a refinery the residual materials are of little value and are typically charged to a petroleum coker or used as asphalt and the like. Typically such heavy crude oils also have a high metals content in the residual materials which reduces the value of any petroleum coke produced from such residual materials.
In U.S. Ser. No. 08/834,009 entitled "Method for Producing Heavy Crude Oil Via a Wellbore From a Subterranean Formation and Converting the Heavy Oil Into a Distillate Product Stream" filed Apr. 12, 1997 by Steven D. Crane and Gary L. Beer and assigned to Atlantic Richfield Company and in U.S. Ser. No. 08/834,007 entitled "Method for Producing From a Subterranean Formation Via a Wellbore, Transporting and Converting a Heavy Crude Oil Into a Distillate Product Stream" filed Apr. 12, 1997 by Steven D. Crane, Gary L. Beer and Harrison F. Blacker and assigned to Atlantic Richfield Company processes are disclosed wherein distillable product streams are recovered from heavy crude oil by atmospheric distillation and by vacuum distillation. The residues from the distillation process or the vacuum distillation process are passed to a fluidized bed for combustion to produce heat, steam, electricity or a synthesis gas. While such processes are effective to produce a distillate hydrocarbon product stream from a heavy crude oil, vacuum distillation is limited to separation of distillates having a boiling point at atmospheric pressure below about 1,060.degree. F. Heavy crude oils contain distillable and refinable hydrocarbonaceous materials which are either incompletely recovered or which are not recovered to any substantial extent in the vacuum distillation process. It is desirable that these distillable materials be recovered from the heavy crude.
Accordingly, a continuing search has been directed to methods for producing such heavy crude oil, at remote sites and marketing both the valuable distillable hydrocarbons and the by-products from the non-distillable residues economically.